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ring end gap?

Posted By: 65rbdodge

ring end gap? - 12/19/08 07:29 PM

i putting together a stock rebuild 318. its a stock bore and the cyls. have been honed. i have a set of std. hastings moly rings, my end gap at both the top and bottom of the cyl. is .030, is this to much? do i need a different set of rings? the box says it should be a minimum of .015 but it doesnt say what the max should be.
Posted By: RapidRobert

Re: ring end gap? - 12/19/08 07:49 PM

.004" per inch of bore on the top ring & .003 on the 2nd ring per inch of bore(for non KB hyper pistons), for you it'd be 15 tho & 11 thou. 30 is too much but it would work but it would work much better with a tighter set of moly rings or may even require the extra $$ for a file fit set. The amt of wear plus the honing opened it up a bit & since circumference = Pi X diameter, a .001" increase in dia(from the honing/wear) will increase the ring gap 3.14"
Posted By: dOc !

Re: ring end gap? - 12/19/08 07:54 PM

Way WAY toooo big IMO.

How much is your piston-to-wall ?
Posted By: dmerc

Re: ring end gap? - 12/19/08 08:34 PM

Perfect gap for nitrous, but a little too much for stock. Having said that I put rings in an engine that had been overbored by .002 and the top ring gap was .022. The engine ran fine and didn't smoke. If you are short on money put it together or get some file fit rings. Really sounds like a tired engine that needs to be bored out.
Posted By: buildanother

Re: ring end gap? - 12/19/08 11:37 PM

Your cylinders must be worn a bit much, or you would not have such a strange fit of new ring set.
Posted By: fastmark

Re: ring end gap? - 12/19/08 11:43 PM

The ring end gap is the least of your problems. I bet you have lots of cly taper and a large piston to cly wall clearance. If the motor should have been bored out and it wasn't, then you will have lots of clearance in those areas. I would not get file to fit rings because if you set it for the top and have lots of taper, you will be too tight at the bottom. The first tool an engine builder needs is a good set of mics and snap gauges( or dial bore gauge).You will use them for the rest of your life. If you have .005 or more taper, then put it together and save for some pistons and a bore job later. Mark
Posted By: moper

Re: ring end gap? - 12/20/08 12:55 AM

Quote:

The ring end gap is the least of your problems. I bet you have lots of cly taper and a large piston to cly wall clearance. If the motor should have been bored out and it wasn't, then you will have lots of clearance in those areas. I would not get file to fit rings because if you set it for the top and have lots of taper, you will be too tight at the bottom. The first tool an engine builder needs is a good set of mics and snap gauges( or dial bore gauge).You will use them for the rest of your life. If you have .005 or more taper, then put it together and save for some pistons and a bore job later. Mark




Did you check and measure the gap in a bunch of spots up and down the bore? You can set the gap at the tightest point. I use the ring manufacturers recommended gap, or the KB adjustment for them. I also ad about 5% tothe second ring gap. You dont want it as tight as the top ring.
Posted By: pacifica

Re: ring end gap? - 12/20/08 01:14 AM

Quote:

i putting together a stock rebuild 318. its a stock bore and the cyls. have been honed. i have a set of std. hastings moly rings, my end gap at both the top and bottom of the cyl. is .030, is this to much? do i need a different set of rings? the box says it should be a minimum of .015 but it doesnt say what the max should be.




.030 is more than you would want in a
"good" rebuild. But if you are doing an "economy" overhaul then it will work, although it will probably use a little more oil than you'd like.
Posted By: dOc !

Re: ring end gap? - 12/20/08 04:33 AM

cylinder taper ? ... ?

With 030 ring gap and both bottom and top? I will bet that he might have near or over .010 piston-top-wall.

Not good.
Posted By: 68Fastback

Re: ring end gap? - 12/20/08 05:08 AM

Did you file the rings to that dimension or is that what you are getting with them in the bore. By chance did you measure the bore thru the intended stroke.
Posted By: MR_P_BODY

Re: ring end gap? - 12/20/08 05:32 AM

.030 is way too much. Are you using the original
piston that were in it? I'd be looking for a bore
job on it and a set of KB pistons or any other
inexspensive set(if your going inexspensive) and a
set of rings. If you put it together like that you
wont be happy at all, its going to have alot of blow by
and soon you will be pulling the engine AGAIN and
I dont think any of us cares to do this(most dont)
Posted By: 68Fastback

Re: ring end gap? - 01/01/09 07:44 PM

Any update on your situation.
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